The invention relates to an actuating device for lifting and lowering a landing lever carrying a magnetic-head assembly of a drive mechanism of a magnetic-disk storage apparatus. The storage apparatus has a front opening for the insertion of a flexible diskette such as those commonly called a "floppy disk". The opening can be closed by means of a pivotal front cover.
U.S. Pat. No. 3,678,481 describes a drive mechanism for a diskette which can be inserted after a cover, which extends over the entire drive mechanism, has been opened. By closing the cover, the diskette is centrally clamped between a clamping cone and a drivetable and is set into rotation. The protective cartridge of the diskette then remains stationary. This enclosure has a radial aperture through which the write and read head assembly can be lowered onto the flexible magnetic disk. For this purpose, there is provided an electromagnet whose armature extends up to the landing lever on which the magnetic head is arranged. When the electromagnet is energized, its armature releases the landing lever which then positions the magnetic head assembly on the magnetic disk under spring force. The armature also carries an adjustable resilient plate on which a pressure pad is arranged. When the magnetic head is lowered onto the magnetic disk, this pressure pad is urged against the diskette cartridge. This ensures a smooth rotation of the magnetic disk.
The electromagnet is program-controlled and can be actuated independently of the position of the cover. As a result, it is possible to remove the diskette from the drive mechanism without the magnetic-head assembly being lifted off the diskette. This may give rise to damage to the diskette and the magnetic head. Also, the known construction is intricate and requires a special control circuit for the magnets.
Moreover, it is known from U.S. Pat. No. 4,415,940 to provide the landing lever which carries the magnetic-head assembly with a cross-arm which cooperates with a shift lever which is inclined on both ends. When this shift lever is moved by the diskette, the magnetic-head assembly is lifted or lowered. For this purpose, the shift lever is moved by the diskette against the action of the spring, so that the magnetic-head assembly is automatically lifted and subsequently lowered when the diskette is inserted into or removed from the drive mechanism. A disadvantage of this is that the ejection device carrying the shift lever has to be moved by the diskette when it is inserted. The frictional forces between the inclined shift-lever arm and the cross-arm then act on the diskette. This increases the likelihood of the diskette being damaged.